The present invention concerns a centrifugal chip separator having an improved blade arrangement that facilitates adjustment, maintenance, and repair of the chip separator.
Centrifuge devices are known in prior art for continuously removing liquid from metal chips, turnings, or other agglomerated scrap material. For example, see U.S. Pat. Nos. Re 35307; 3,366,318; and 4,186,096. These centrifuge devices include a centrifuge bowl where the liquid is centrifugally separated from the agglomerated scrap as the bowl is spun. Blades are positioned in the bowl to motivate the agglomerated scrap around the bowl. The bowl and blades are subject to severe wear and must often be repaired or replaced, because the metal chips are abrasive and cause extensive wear as they impact and slide across the bowl and blade surfaces. The blades in particular are subject to wear since they impact and motivate the scrap as the scrap is initially introduced into the bowl and as the bowl is spun. Repair or maintenance of bowls and blades has been achieved in different ways, such as by replaceable liners, replaceable bowls, replaceable blades, hardened material welded into bowls and liners, etc. However, sooner or later, all blades and/or bowls need repair or replacement. The repair and/or mainenance is a very time-consuming and potentially hazardous job due to the confined space in which the work must be performed. Further, the repair and/or maintenance is unfortunately a very messy and smelly job due to the residue of particles and liquid in the centrifuge bowl. It is highly desirable to provide an arrangement that facilitates repair and/or lets maintenance workers do their job without placing themselves in the potentially hazardous situations.
Reissue patent Re. 35,307 discloses a centrifuge that has independently removable blades. However, in Reissue '307, the screw heads are located inside the bowl in exposed positions. As a result, the hex recess or slot in the screw heads may wear, making it difficult to engage the screw head with enough torsional force to rotate and remove the screw. In extreme cases, the screw head may wear away to such an extent that the hex recess or slot is no longer present, and/or the head is so worn that the blades may not easily be removable. This would potentially require complete replacement of the entire bowl or blade assembly. One embodiment shown in patent '307 includes multiple discrete recesses formed on an inside surface of the bowl wall. This may reduce wear on the blades in some circumstances, but discrete recesses are expensive to form in centrifuge bowls, such that this adds considerably to the expense in centrifuge devices having bowls with recesses therein. Notably, the design of FIGS. 2-5 in Reissue '307 fails to provide the claimed advantage of the elimination of bowl wear since wear occurs not only on the wear shoe but on the bowl at the interface between the blade wear shoe and bowl recess. A blade with the wear shoe above the surface of the inner bowl wall is far better than the recessed design since the chips are elevated away from the inner bowl wall surface.
As inferred above, one reason that maintenance of the centrifuge bowl and the blades is difficult is because it requires that the mechanic enter or reach inside of the centrifuge bowl. Bowls are normally very dirty, oily, and slippery, since they are covered with particles and debris mixed with coolant, oil, cutting fluids, and residue from the centrifuging process. Not only is the environment unpleasant and potentially dangerously slippery, it is also very confined, dark, and generally difficult to work in. Depending on how unclean the bowl is, the particles and debris can make it difficult to properly "seat" a replacement blade, such as the blades shown in patent Re35307, against a bowl interior surface.
Therefore, an apparatus solving the aforementioned problems and having the aforementioned advantages is desired.